Apparently, carrying out an exothermic reaction along the length of a nanotube can result in a "thermopower wave" which results from "electron entrainment" (a wave propagating along the nanotube which pushes electrons along, resulting in a power spike)

It's exploiting the fact that the electrons are confined to the tube/wire, and stampeding them along it, like forcing a pressure wave through a tight channel.

The electrons and the wave that's driving them can't just go in any old direction, so the wave's energy is then amplifying the electrons' energy, to give the current more power. They're claiming 100 times more energy than a Lithium-ion battery.

So obviously this system is not reversible, so you only use it once, like a match.

But this "quantum fuse" is then able to drive a powerful current. I'm wondering if it could power a VASIMR-style plasma-thruster instead of a nuclear reactor. Things like plasma-thrusters need a lot of power to operate: